.countdown {
  width: 100%;
  height: 80%;
  transform-style: preserve-3d;
  perspective: 1000px;
}

.countdown:before {
  content: '';
  
  bottom: -50px;
  left: 0;
  width: 100%;
  height: 10px;
  background: #000;
  border-radius: 50%;
  filter: blur(14px);
  animation: shadow 1s linear;
}

@keyframes shadow {
  0%, 100% {
    transform: scale(0.5);
  }
  
  50% {
    transform: scale(1);
  }
}

.countdown .number {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  transform: rotateY(270deg);
  animation: animate 10s linear ;
}

.countdown .number:nth-child(1) {
  animation-delay: 0s;
}

.countdown .number:nth-child(2) {
  animation-delay: 1s;
}

.countdown .number:nth-child(3) {
  animation-delay: 2s;
}

.countdown .number:nth-child(4) {
  animation-delay: 3s;
}

.countdown .number:nth-child(5) {
  animation-delay: 4s;
}

.countdown .number:nth-child(6) {
  animation-delay: 5s;
}

.countdown .number:nth-child(7) {
  animation-delay: 6s;
}

.countdown .number:nth-child(8) {
  animation-delay: 7s;
}

.countdown .number:nth-child(9) {
  animation-delay: 8s;
}

.countdown .number:nth-child(10) {
  animation-delay: 9s;
}

.countdown .number h2 {
  margin: 0;
  padding: 0;
  font-size: 20em;
  color: #fff;
}

@keyframes animate {
  0% {
    transform: rotateY(90deg);
  }
  
  10%, 100% {
    transform: rotateY(-90deg);
  }
}